How do you download rct3 steelworks if you have a mac and steam?

To download RCT3 Steelworks on a Mac using Steam, first ensure you have the Steam client installed and logged into your account. Then, search for "RollerCoaster Tycoon 3: Complete Edition" in the Steam store, as Steelworks is included in this version. Purchase and download the game, and once installed, you can access it from your Steam library. Make sure to check for any compatibility settings if you encounter issues running the game on macOS.